1. Field of the Invention
The present invention relates to a backlight module; specifically to a reflector for use in a backlight module and a method for making the same.
2. Descriptions of the Related Art
Common liquid crystal displays (LCDs) primarily comprise a liquid crystal panel and a backlight module. The backlight module provides a light source for the liquid crystal panel to display images on the liquid crystal display. Since the LCD has desirable features, such as thinness, light weight and convenient portability, its demand in recent years has grown rapidly and now dominates the market share.
Generally speaking, several backlight module structures have been developed to meet various requirements. A backlight module that is usually applied in a small sized panel comprises an edge type structure which is characterized by a light source design comprising a light guide plate with side incident light. The edge type backlight module is light, thin and consumes little power. Because of its features, this module has been commonly used as the light source for notebooks.
The backlight module with the edge type structure comprises a light source installed on one side of the whole module for providing light for the LCD. Moreover, the backlight module further comprises a light guide plate and a reflector, wherein the reflector contains the light source that connects with the light guide plate. When the light source emits a light beam, the light guide plate transforms that light beam into a uniform plane light beam for displaying LCD images.
FIG. 1 shows a conventional backlight module 10 comprising a light source 11, a light guide plate 12 and a reflector 13. The display often has separate and contrasting bright and dark stripes, as shown next to the side light source 11. The stripes affect brightness uniformity for the LCD. As shown in FIG. 2, the stripes are usually called MURA defects which may result from many reasons. One of the reasons is that light can leak through a junction between the light guide plate 12 and the reflector 13.
Currently, there are several methods that have been developed to prevent the MURA phenomenon, such as coating light absorption materials on the inner side 14 of the reflector 13 near the junction of the light guide plate 12 to reduce non-uniform brightness. However, this method does not support whole light usage and degrades the overall brightness of the LCD accordingly. Another method coats the light absorption materials on the inner side 14 of the reflector by processing the surface with three to four printing processes to absorb or scatter the light proximal to the junction. Although this method provides slightly more uniform light, there is still an overall loss in the brightness of the LCD. Furthermore, the manufacturing processes are complicated and thus, increase costs undoubtedly.